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प्रश्न
The following are the marks obtained by 70 boys in a class test:
| Marks | No. of boys |
| 30 – 40 | 10 |
| 40 – 50 | 12 |
| 50 – 60 | 14 |
| 60 – 70 | 12 |
| 70 – 80 | 9 |
| 80 – 90 | 7 |
| 90 – 100 | 6 |
Calculate the mean by:
Short-cut method
उत्तर
Short-cut method
|
Marks |
No. of boys |
Mid-value |
A = 65 |
fidi |
| 30 – 40 | 10 | 35 | –30 | –300 |
| 40 – 50 | 12 | 45 | –20 | –240 |
| 50 – 60 | 14 | 55 | –10 | –140 |
| 60 – 70 | 12 | A = 65 | 0 | 0 |
| 70 – 80 | 9 | 75 | 10 | 90 |
| 80 – 90 | 7 | 85 | 20 | 140 |
| 90 – 100 | 6 | 95 | 30 | 180 |
| Total | 70 | –270 |
`barx = A + (sumf_i d_i)/(sumf_i)`
= `65 + ((-270)/70)`
= 65 – 3.86
= 61.14
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संबंधित प्रश्न
The following table gives the weekly wages of workers in a factory.
| Weekly wages (Rs) | No. of workers |
| 50 – 55 | 5 |
| 55 – 60 | 20 |
| 60 – 65 | 10 |
| 65 – 70 | 10 |
| 70 – 75 | 9 |
| 75 – 80 | 6 |
| 80 – 85 | 12 |
| 85 – 90 | 8 |
Calculate the mean by using:
Direct Method
Find the mode of the following data:
7, 9, 8, 7, 7, 6, 8, 10, 7 and 6
The marks of 200 students in a test were recorded as follows:
| Marks | No. of students |
| 10-19 | 7 |
| 20-29 | 11 |
| 30-39 | 20 |
| 40-49 | 46 |
| 50-59 | 57 |
| 60-69 | 37 |
| 70-79 | 15 |
| 80-89 | 7 |
Construct the cumulative frequency table. Drew the ogive and use it too find:
(1) the median and
(2) the number of student who score more than 35% marks.
Find the mean (correct to one place of decimal) by using short-cut method.
|
x |
40 |
41 |
43 |
45 |
46 |
49 |
50 |
|
f |
14 |
28 |
38 |
50 |
40 |
20 |
10 |
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The mean of a certain number of observations is 32. Find the resulting mean, if the observation is, divided by 0.5
Mean of 5 numbers is 20 and the mean of the other 5 numbers is 30. Find the mean of all the 10 numbers taken together.
Find the median of 1,3,4, 5, 9, 9 and 11
Find the mean and the median of: 5, 8, 10, 11,13, 16, 19 and 20
